114 Clark, Tail-feathers and Coverts. [ April 



once that little could be learned from skins, at least without seri- 

 ously damaging them. This is no doubt one of the main reasons 

 why our knowledge is so incomplete. Fortunately the Museum of 

 Comparative Zoology has a very large and varied collection of 

 alcoholic birds, which thanks to the kindness of the Director, Mr. 

 Samuel Henshaw, and the Associate Curator of Birds, Mr. Outram 

 Bangs, is freely accessible to me. I have thus been able to examine 

 the tails and major coverts of more than a hundred genera of birds, 

 representing most of the larger and more important orders. The 

 results of this hasty and superficial work are given here and are, 

 I believe, of considerable interest and perhaps of some importance. 



The major upper coverts of a bird lie in a single series directly 

 above the rectrices. In the vast majority of birds, they are quite 

 distinct from the other coverts, which rise from the posterior part 

 of the spinal pteryla, and are so definitely circumscribed that their 

 number permits of no discussion. In some birds however, notably 

 the loon and the penguin, it is exceedingly difficult to distinguish 

 any particular series of coverts as "major" and one can simply 

 assume that the series next above the rectrices should receive that 

 title. But in such cases, it is hard to determine where the outer 

 end of this series, on each side, is and there is room for considerable 

 difference of opinion. I have seen no case however where I was 

 unable to satisfy myself as to the number of major coverts. In 

 some birds, notably the woodpeckers, a series of contour feathers 

 on the sides of the pygidium is continuous with the series of major 

 coverts, and in such cases there is again some trouble in definitely 

 limiting the covert series. 



The relative position of covert and rectrix shows some diversity. 

 As a rule each covert is inserted at the base of its own rectrix and 

 the line of covert-pits (on a plucked bird) is parallel to the series 

 of rectrix-pits. But sometimes the two series are not parallel, 

 the outer covert-pits being distinctly further from the rectrices at 

 the corners of the pygidium than near the middle. As a rule, the 

 middle pair of tail-feathers is the largest and they are inserted 

 at a higher level than the others; as a result their coverts are 

 pushed to the outer side. Thus covert 1 does not lie above rectrix 1 

 but between the bases of 1 and 2 or over rectrix 2, and in some cases, 

 where the middle rectrices are particularly stout as in the Pileated 



